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SAFETY IN WELDING & CUTTING

2

INTRODUCTION • Intense heat is generated during welding

and cutting of metals

– Heat obtained from inflammable gases (C2H2) or electricity to the objects being welded or cut

• Employees exposed to the hazards created by welding and cutting operations shall be protected

• The main hazards are: – Electric shock

– Arc radiation

– Fumes, Gases & dust

– Compressed gases

– Fire & explosion

– Noise

ELECTRIC SHOCK • Results due to:-

– Damaged insulation of cables

– Lack of adequate earthing

– current passing through welder’s body (The heart

may cease to function, if current level exceeds

25mA)

– High RH, Ambient temp ›30°C & presence of

chemically active substances in atm damaging

electric insulation

• Cause severe burns & loss of life

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ARC RADIATION • The welding arc emits UV & IR rays

• UV rays can damage both the eyes & the skin.

Even an accidental exposure to the UV light from

an arc can cause a condition known as “Arc Eye”

(watering of eyes & inability to tolerate light)

• Exposure of skin to UV radiation is also harmful.

Prolonged exposure causes severe burning &

skin peels off.

• Exposure to IR rays may cause cataract of the

eyes. Proper glass filter to be used

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GASES, FUMES & DUST • Fumes & CO are produced during pre heating of

work using gas, charcoal, oil or coal fired furnace

• Effects of fumes include irritation of the respiratory

resulting in dryness of throat, coughing, chest

tightness & breathing difficulties.

• Weld fumes :

– injurious to health if the electrode coating contains

fluorides

– with high Cr

– galvanised or any coating

– much more dangerous when done in confined spaces

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GASES,FUMES & DUST • Gases:

– Results due to-

• decomposition of fluxes & by the effects of UV

& IR radiations on the atmospheric gases

(3O2 2O3), which when inhaled regularly

over long periods may result in serious effects

on the welder’s health.

• Absorption of O2 during combustion (CO)

• Oxidation of N2 in the air (nitrous fumes)

• Escape of gases used for combustion in

welding / cutting

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GASES,FUMES & DUST

• Dusts:

– Produces harmful fumes if the electrode

contains Pb

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COMPRESSED GASES

• Gases used in welding & cutting are the fuel gases

(acetylene, LPG), oxygen & shielding gases

(argon, helium, nitrogen & CO2)

• Escaping fuel gases may cause fire or an

explosion

• Compressed gas cylinders should not be exposed

to sun light or heat as this may lead to increase of

pressure leading to explosion

• The temp of gas cylinders should not exceed 54°C

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FIRE & EXPLOSION • Results due to:

– Inadequate connections

– Damaged insulation cables

– ignition of combustible or inflammable material lying in the vicinity of weld zone Burns from freshly welded metal.

– Sparks, molten metal globules & hot slag

– Hot electrode stubs

– gas cylinder valves leaking

– misuse of oxygen

– rubber hoses leaking

• Involves loss of life & damage property 16/06/2015 9

Contd-------

Explosion can take place when:-

• Oil /grease comes in contact with any

pipe, valve, etc. carrying O2.

• welding or cutting of a closed vessel with

inflammable liquids or gases

• Fuel gas cylinders exposed to high temp.

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NOISE

• Normal welding operations do not cause

much noise but gouging & plasma arc

cutting with high currents can create

excessive noise

• Noise due to welding, cutting, grinding,

chipping & other machining operation might

be going on simultaneously in the welding

shop

• Noise above 80 db is considered harmful &

above 120 outright dangerous 16/06/2015 11

PERSONAL PROTECTIVE EQUIPMENT

• The risks associated with welding/cutting can be reduced by proper use of Personal Protective Equipment (PPE)

• A set of PPE have been published by ISI and many other similar International Organisations.

• Appropriate protective clothing required for any welding operation will vary with the size, nature & location of the work to be performed.

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WHAT IS SAFETY ?

Definition: “Safety is the measure of

relative freedom from risks or dangers in

any environment”.

Nothing is 100% safe in any condition. -by Gloss and Wardle

Safety means:

• Free from Hazards

• Free from Risk

• Free from accident

• Free from illness

• Free from harmful effects, etc.

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WHY WELDING SAFETY IS REQUIRED ?

• To avoid occupational diseases

– Occupational disease means:

• A disease which affects the human body due

to routine work.

• Substances such as silica, asbestos, Be, Cd,

metals, organic chemicals cause disease of

the respiratory system

• To protect property from fire/explosion

• To prevent human loss due to fire/explosion

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VARIOUS ASPECTS OF WELDING &

CUTTING SAFETY

• Safety recommended for operation of:-

– gas welding & cutting equipments.

– arc welding & cutting equipments.

• Explosion, fire & other hazards.

• Ventilation & health protection.

• Protection of welders.

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SAFETY RECOMMENDATIONS IN GAS

WELDING & CUTTING

Cylinders to be:

• kept upright in such a way so that they do not fall.

• fitted with cap, when not in use.

• stored in a well protected place

• Stored cylinders of acetylene & oxygen separately

• moved by tilting & rolling on their bottom edge with valves closed

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SAFETY RECOMMENDATIONS IN GAS

WELDING & CUTTING

• Cylinders not to be: – exposed to welding flame, direct sunlight, etc.

– used as rollers for moving materials.

• Welding not be done in confined areas.

• Fire extinguishers / sand to be available at hand.

• Cylinder valves to be closed when work is

finished.

• The nos. & markings on the cylinder & its safety

devices not to be tampered

• Frozen valves or regulators to be thawed with

hot water, never by flame.

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SAFETY RECOMMENDATIONS IN GAS

WELDING & CUTTING

• Gas torches & tips to be stored in clean boxes

• blow pipes & other apparatus to be cleaned

internally at a regular interval.

• The slag accumulated at the blow pipe tip to be

frequently removed

• Gas flame not to be played on the cylinder or

their attachments.

• Hot jobs not to be picked up.

• Painted or galvanised surfaces to be welded in

well ventilated space.

OTHER PRECAUTIONS

• Keep hoses away from sharp edges and abrasive

surfaces or where vehicles can run over them

• Do not allow hot metal or spatter to fall on hoses

• Regular checking of all connections and

equipments for faults and leaks.

• Immediate repair or replace leaking components.

• Leaking hoses should not be repaired, but they can

be shortened to remove a damaged section

• Dirt, grease and other contamination increases the

amount of fumes generated which is very toxic.

Avoid all these as far as possible.

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OTHER PRECAUTIONS • Oxygen leaks also increase the fire risk. Clothing

contaminated with oxygen, even fire-retardant

clothing, will catch fire easily and burn very fiercely

• oxygen reacts explosively with oil and grease

• never use oxygen to blow dust off clothing

• never allow oil or grease to come into contact with

oxygen valves or cylinder fittings

• shut off the torch when not in use. Do not leave a

lighted torch on a bench or the floor

• clamp the work piece, avoid holding it by hand.

• Oxy/fuel equipment is relatively easy to use but

users may still need some instruction or training in.

• always provide adequate ventilation

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TWO CYLINDERS

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GAS CYLINDERS & THEIR

ATTACHMENTS

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SAFETY RECOMMENDED IN ARC

WELDING & CUTTING • All equipments to be inspected periodically &

maintained in safe working order at all times.

• A disconnecting switch to be provided at or near each welding machine

• Working area & floor to be kept clean & clear of electrode stubs & metal scrap.

• Be ensure that welding equipment is adequately earthed.

• not to look at electric arc with the naked eye

• Welding cables: – should have complete insulation

– be capable of handling the max current required for the work.

– should be free from repair

– to be kept dry (free from grease & oil).

FIRE HAZARD PROTECTION Following precautions can help in preventing

fire:

• move work piece to a safe location for

carrying out hot work

• remove nearby combustible materials (wood,

paper, textiles plastics, flammable liquids)

• protect nearby combustible materials that

cannot be moved. Use suitable guards or

covers such as metal sheeting or fire-

retardant blankets

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FIRE HAZARD PROTECTION

• use flame-resistant sheets or covers

to prevent hot particles passing

through openings in floors and walls

(doorways, windows, cable runs, etc)

• prevent flame, heat, sparks or hot

spatter from landing on the hoses

• keep fire extinguishers nearby.

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SHOCK HAZARDS PROTECTION

• Necessary precautions to minimise electric

risk can best be done by ensuring proper

insulation of cables & reliable earthing of

welding equipments

PERSONAL PROTECTIVE

EQUIPMENT (PPE)

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PPE: FOR WELDING & CUTTING

Welders must wear suitable protective

equipments.

They:

• protect against hazards (burns, sparks,

spatters,electric shock, radiation (UV, IR),

Slag, heat, hot metals, heat, fumes, gases,

etc).

• may be procured from regular agencies &

as per the specification

PPE: FOR WELDING & CUTTING

Regular agencies:

• ANSI: American National Standards

Institute

• OSHA: Occupational Safety & Health

Administration

• NFPA: National Fire Protection

Association

• AWS: American Welding Society

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SPEC FOR PPE FOR WELDING &

CUTTING

1. Eye protection: ANSI Z 49.1 & OSHA 29 CFR

1910.252

2. Head protection: ANSI Z 49.1&OSHA 29

CFR1910.252

3. Ear protection: ANSI Z 49.1 & OSHA 29 CFR

1910.252

4. Foot protection: ASTM F 2412 & 2413

5. Hand protection: ANSI Z 49.1

6. Body protection: ANSI Z 49.1

7. Respiratory Protection Equipment :ANSI Z 49.1

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HAND PROTECTION (GLOVES)

• Protects the hand from:

– Electric shock

– Flame

– Hot parts

– Sharp or flying metals &

– Arc rays

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HAND PROTECTION (GLOVES)

Gloves should be:-

• Dry and moisture resistant

• Free from holes

• Flame resistant

• Electrically and thermally

insulated

• Flexible--allow easy movement &

full range of motion

• Comfortable--proper fit and size

• Durable, tough, and long lasting

• Cut, scrape, tear and puncture

resistant

Hand gloves

EAR PROTECTION (EAR

PLUG/MUFF)

• Protects from:

– Flying sparks

– Spatter

– Burns

– Hearing

– hearing loss

• Ear plug/ muff should be:

– fire-resistant

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EAR PLUG WITH CAP

EAR PLUG

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HEAD PROTECTION (HELMET)

Safety helmets

Safety helmets should be:

• uv-resistant

• facilated with International

design for ventilation of air to

keep head cool

• made of high density poly

ethylene (HDPE)

should have:

• adjustable head band

• Protects from:- • Flying sparks • Spatters

• Available in a wide range high quaility in different beautiful colours

EYE PROTECTION(GOGGLES) • Eye protective equipments

available in various designs

• They protect eyes from:-

– getting damaged (retinal burns or permanent blindness) due to:-

» Infra red rays (can cause painful injury to the eye) & ultra violet rays (can burn the skin)

» Filter lens removes approx 99.5% IR & 99.75 % UV

– Flying sparks

– Spatter 16/06/2015 Welding goggles

Chipping goggles

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FOOT PROTECTION (SAFETY

SHOES & BOOTS) • They protect legs & feet from:

• Slag

• Falling off cuts

• Spatters.

• Available in various sizes to suit different persons made from different raw materials like:

– Asbestos

– Leather steel toed

– Rubber

– Vinyl (PVC)

– Canvas

SAFETY SHOES

FOOT GUARD WITH

RUBBER TOED

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FOOT PROTECTION (LEG GUARD)

Leg guard

• It protects from: • Slag

• Falling off cuts

• Spatters available in a wide range of well designed

• Manufactured from high

quality leather.

• High quality raw materials

makes leg guards flame

resistant.

• Also come in asbestos and

aluminized finish.

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BODY PROTECTION (APRON) Protect complete body from:-

• Flying sparks

• Hot spatter particles

• It should be:-

– In good condition (no holes & tears).

– Dry, clean (free of oil, grease, or solvents)

– Flexible--allow easy movement & full range of motion

– Comfortable--proper fit and size

– Durable

*Available in a wide range made from different quality

raw materials like:-

– leather, rubber, vinyl (PVC).

*also available in asbestos / aluminized finish.

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BODY PROTECTION (APRON)

SAFETY APRON SAFETY APRON

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BODY PROTECTION (WELDING SUIT &

SAFETY BELT)

WELDING SUITS:

• Available in a wide range made

from high quality raw materials:

– rubber, vinyl (PVC).

• Also available in asbestos &

aluminized finish

SAFETY BELTS:

• used in jobs that involve a high risk of falling like construction sites, etc

• Available in a wide variety made of Nylon

• Durable in quality

WELDING SUITS

SAFETY BELTS

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WELDING RESPIRATOR

Welding Respirators:

• Welding produces fumes and gases

hazardous to health

• Avoid breathing these fumes & gases

• Use adequate ventilation.

• Protect from:

– Welding fumes

– Welding fumes can affect :

• Lungs

• heart

• kidneys

• nervous system, etc

• Available in different types & sizes

Welding Respirators

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THANK U

THANK YOU